The present disclosure relates to a method for manufacturing a gallium oxide based substrate, a light emitting device, and a method for manufacturing the light emitting device.
Nitride semiconductors attract a great attention in the optical device and high-power electronic device development fields because of their high thermal stability and wide bandgap energy. In particular, blue, green and UV light emitting devices using nitride semiconductors have been commercialized and widely used.
Nitride semiconductor light emitting devices include a nitride semiconductor layer that is organic-chemically deposited over a sapphire substrate being a dissimilar substrate.
The sapphire substrate has an electrically insulating characteristic. Thus, in order to apply a voltage to the nitride semiconductor layer, it is necessary to partially etch the nitride semiconductor layer or remove the sapphire substrate.
The nitride semiconductor light emitting devices may be classified into lateral type nitride semiconductor light emitting devices and vertical type nitride semiconductor light emitting devices according to position of an electrode layer.
In the case of the lateral type nitride semiconductor light emitting devices, a nitride semiconductor layer is formed over the sapphire substrate, and two electrode layers are formed to be arranged over the nitride semiconductor layer.
In the case of the vertical type nitride semiconductor light emitting devices, a nitride semiconductor layer is formed over the sapphire substrate, the sapphire substrate is separated from the nitride semiconductor layer, and two electrode layers are formed to be arranged on and under the nitride semiconductor layer, respectively.
Meanwhile, the lateral type nitride semiconductor light emitting devices need to remove a portion of the nitride semiconductor layer in order to form two electrode layers, and has limitations in that the reliability and efficiency of light emission characteristic are degraded because of non-uniform current distribution.
Furthermore, the vertical type nitride semiconductor light emitting devices need to separate the sapphire substrate.
Therefore, many researches have been made on vertical type nitride semiconductor light emitting devices, in particular, nitride semiconductor light emitting devices that need not separate the substrate by the use of conductive substrates.